The long-term aim of this project is to understand in greater depth the biology of the steroid-synthesizing cell. There are several areas of uncertainty as to the exact molecular events involved in 1) initiation of steroid synthesis, 2) subcellular, intercompartmental transport of steroid precursors and intermediates and, 3) secretion of steroid products. In addition, the adrenal cortex is zonated with the outer zone cells synthesizing aldosterone (mineralocorticoid) and the inner zone cells synthesizing cortisol (glucocorticoid) and dehydroepiandrosterone (androgen). Yet, nothing is known of the cell-cell (zone-zone) inter-action of the various zones. Current areas of research involve: 1) an examination of the role of microtubules and contractile proteins in steroid synthesis; 2) identification and characterization of non-catalytic proteins (membrane bound and/or soluble) that interact specifically with steroid precursors and intermediates; 3) measurement of subcellular pool sizes of cholesterol and pregnenolone under various conditions; 4) establishing the methodology for performing superfusion studies and, 5) morphological studies utilizing the electron microscope.